Boeing [NYSE: BA] now has six aircraft in its KC-46 tanker test program, expanding its ability to complete ground and flight-test activities as it progressestoward first deliveries to the U.S. Air Force.

The newest KC-46 aerial refueling aircraft, the second low-rate initial production plane, completed its first flight April 29. Its test activities will help ensure the KC-46 can safely operate through electromagnetic fields produced by radars, radio towers and other systems.

Boeing [NYSE: BA] now has six aircraft in its KC-46 tanker test program, expanding its ability to complete ground and flight-test activities as it progressestoward first deliveries to the U.S. Air Force.

The newest KC-46 aerial refueling aircraft, the second low-rate initial production plane, completed its first flight April 29. Its test activities will help ensure the KC-46 can safely operate through electromagnetic fields produced by radars, radio towers and other systems.

The note about Boeing and the supplier not realizing how much documentation needed for the WARP could probably be blamed on lost of experience internal to Boeing (or the right mix of experience people did not get on to the tanker Commercial operation - this mix is important as you need both commercial (FAA) and military (WARP) experience working closely to cover all aspect of the cert), lack of experience from the WARP designer and manufacturer with respect to the FAA cert process. (They probably never had to go through this type of cert before as all their previous cert was through a military modification process that only requires a military cert).

That is my hypothesis.

bt

Boeing in it's infinite wisdom closed their Wichita operation which had lots of tanker experience. That knowledge base was instead spread to teh four winds.

Boeing in it's infinite wisdom closed their Wichita operation which had lots of tanker experience. That knowledge base was instead spread to teh four winds.

Yes, Boeing's original plan was to build them as green commercial airliners and send them to Wichita for conversion (as I believe was done with the KC-767 family), but (rightly, IMO) came to the conclusion that commercial 767-2C sales would probably be zero so by doing the military-related work on the FAL itself would cut down on conversion time and cost. The learning curve has been rough, but over time, it should be the better choice as doing it on the FAL will be easier than tearing the plane apart again to fit everything in.

If those are WARPS they look way out at the extreme ends of the wings, is there a capability or requirement to refuel 3 a/c at once - 2 Navy 1 Air Force?

Not gonna happen.

In the KC-10, simultaneous boom and WARP receivers are prohibited, due to inadequate receiver separation distance. Different airspeed requirements and emergency separation (breakaway) response times between boom AR and drogue AR are also a factor. Simultaneous centerline drogue and WARP receivers are also prohibited in the KC-10, also due to inadequate receiver separation distance.

If those are WARPS they look way out at the extreme ends of the wings, is there a capability or requirement to refuel 3 a/c at once - 2 Navy 1 Air Force?

I asked when I toured the program earlier this month (along with Ostrower and others). The answer is maybe for foreign sales of the KC-46.

Three planes at once was not a USAF requirement, b/c there would not be enough wingtip clearance. However, I was told that if a foreign nation wants it, Boeing can provide that capability. I believe the KC-767s delivered to Italy can fuel three planes at once.

What would one say if suddenly, all of the previous testing were invalidated due to the test aircraft not being representative of the production model? Would this be newsworthy?

Are you talking about the FAA or Air Force testing? Are you talking about "all" of the testing or just a particular system?

As far as the FAA is concerned most of their testing (on any airplane) is accomplished prior to the airplane being "representative of a production model". When doing certification work their concern is that the specific system/area they are testing and that any related systems/areas are in final production configuration not the whole airplane.

The tankers seem to be suffering from fuel temperature issues. I monitor the ground comms at BFI and tanker #1 has had issues for the past 3 days having to hold on the ramp and taxiways for up to 30 mins sometimes for the temp to drop to allow a take off. Today it escalated to the point where Fire Rescue was called to douse the wings with water in an attempt to bring the temperature down. Seemed to work, but by the time he'd taxied to the threshold for take off the temp had risen again. Sat there for 20 mins hoping it would drop but no luck so they've had to cancel the flight and return to the stall.

Anyone know why this is a problem on the tankers and seemingly not on other types? It's hardly blisteringly hot at Seattle today.

The tankers seem to be suffering from fuel temperature issues. I monitor the ground comms at BFI and tanker #1 has had issues for the past 3 days having to hold on the ramp and taxiways for up to 30 mins sometimes for the temp to drop to allow a take off. Today it escalated to the point where Fire Rescue was called to douse the wings with water in an attempt to bring the temperature down. Seemed to work, but by the time he'd taxied to the threshold for take off the temp had risen again. Sat there for 20 mins hoping it would drop but no luck so they've had to cancel the flight and return to the stall.

Anyone know why this is a problem on the tankers and seemingly not on other types? It's hardly blisteringly hot at Seattle today.

I think there would be a clearance issue with two V-22 refueling from the WARPS.

Clearance for the V-22 to HAR from the KC-10 happened after I had left the jet, so I'm not 100% certain... but every picture or video I've seen of KC-10 - V-22 operations has been from the centerline drogue.

V-22 "wingspan" is ~84ft at the outboard tips of the proprotors. For the sake of easy math, we'll call the distance from the AR probe to the proprotor tips 40ft.KC-46 wingspan is ~158ft. The WARPs are inboard of the wingtips; my brief search for a measurement was unsuccessful. Again, for easy math, we'll call the distance between WARPs 140ft.Using these simplified (and, admittedly, borderline fictional) numbers, simultaneous V-22s on the KC-46 WARPs gives 60ft lateral separation. I no longer remember what formula USAF uses to determine "safe" receiver separation distance during WARP/MPRS refueling, but I doubt it results in a distance less than one receiver "wingspan" being considered acceptable receiver separation.

I think there would be a clearance issue with two V-22 refueling from the WARPS.

Clearance for the V-22 to HAR from the KC-10 happened after I had left the jet, so I'm not 100% certain... but every picture or video I've seen of KC-10 - V-22 operations has been from the centerline drogue.

Correct... the V-22 is only approved to refuel from the centerline drogue on the KC-10. Not sure if it's a spacing/clearance issue or just the CLD is more stable than the WARPs.

Correct... the V-22 is only approved to refuel from the centerline drogue on the KC-10. Not sure if it's a spacing/clearance issue or just the CLD is more stable than the WARPs.

I read somewhere that the big issue with doing probe / drogue on the KC10 was that once the a/c was fitted that was the only thing it could do as the boom was rendered inop, so in effect a speciality mission just for the Navy or Marines...based on military spending criteria, would it have been better to get the KC10 fitted with WARPS or was that not possible?

Correct... the V-22 is only approved to refuel from the centerline drogue on the KC-10. Not sure if it's a spacing/clearance issue or just the CLD is more stable than the WARPs.

I read somewhere that the big issue with doing probe / drogue on the KC10 was that once the a/c was fitted that was the only thing it could do as the boom was rendered inop, so in effect a speciality mission just for the Navy or Marines...based on military spending criteria, would it have been better to get the KC10 fitted with WARPS or was that not possible?

Pretty sure that's the KC-135. Which requires a boom to drogue adapter to be fitted on the ground. The KC-10 has the boom, and a reel forward of the boom hinge. So it can do both in the same flight.

Pretty sure that's the KC-135. Which requires a boom to drogue adapter to be fitted on the ground. The KC-10 has the boom, and a reel forward of the boom hinge. So it can do both in the same flight.

EDIT:

Yep.

Aircrew call the KC-135 probe attachment the "iron maiden" and hate refuelling from it compared to a standard WARP arrangement as there are a couple of quirks to the refuelling process that make it difficult and more dangerous.

I read somewhere that the big issue with doing probe / drogue on the KC10 was that once the a/c was fitted that was the only thing it could do as the boom was rendered inop, so in effect a speciality mission just for the Navy or Marines...based on military spending criteria, would it have been better to get the KC10 fitted with WARPS or was that not possible?

Sorry for the late response...

As already noted, the KC-135 with the Boom Drogue Adaptor installed becomes a drogue-only tanker until the BDA is removed by the ground crew after landing. The KC-10 has a centerline drogue installed on every aircraft; nearly every mission I flew during my deployments to the sandbox had both boom and drogue receivers.

IIRC, about 1/3 of the KC-10 fleet is modified for WARPs; there are more WARP-capable -10s then there are sets of pods to install on them. The WARPs, unfortunately, are notoriously unreliable, and the customer who pushed the USAF into buying the mod (the US Navy) almost never uses them. The installed pods inflict a not-insignificant drag penalty in all phases of flight, and also inflict some significant takeoff restrictions WRT weather, winds, and runway length. In the 10 years I was a KC-10 boom operator, I only had one mission where the WARPs were a requirement - a movement of a Marine Harrier squadron from Cherry Point to Iwakuni, then another squadron from Iwakuni to Yuma. We had a pod fail on one of our overnight stops at Wake Island that couldn't be fixed. The other -10 on the mission had a pod fail on the very first leg of the mission. We had to get waivers from both the Air Force and the Marine Corps to continue the mission with the centerline drogues only.

Was down at the Museum of Flight this morning and caught a KC-46A going up for a flight. There were also four more birds at the Flight Test Center (along with the 787-10 and what I assume is the 737-9).

Damn! Will the first 6 aircraft which have been used for testing go to the USAF once testing and certification is complete?

AFAIK all 6 test aircraft will be refurbished and will be delivered to the USAF.The first four test aircraft (VH001-VH004) are "real" test wired aircraft and need far more modifications, before delivery to the USAFVH005 and VH006 are later added to the test program to speed up the test flying to cater for further delays and are LRIP aircraft, locally adapted for specific testing.

Operating a twin over the ocean, you're always one engine failure from a total emergency.

A trick that mutes a blaring horn when the autopilots on all Boeing models—except the 787—are manually disconnected could potentially cause an entry-into-service delay for the company’s KC-46 Pegasus tanker, a derivative of the 767-2C freighter.

Considering the 767-2C is only going to be operated by a single customer (the USAF in the KC-46A configuration) during the exemption period, I would expect the FAA to grant this waiver as it should be easy enough to add this into the training regimen for the smallish pool of USAF pilots who will be flying the plane until the software roll-out is ready.

I don't think this will cause any delays, should be able to fix that rather quickly. Don't know were Boeing came up with their 99%, I did it for years along with most of the people I flew with IIRC..

That's the key - if you know how to do it, there is a 100% success rate. If you do not know how to do it, then there is a 1% chance (per Boeing's studies) that you will be successful and this is Boeing's argument - the chances for an Air Force pilot not knowing the procedure accidentally triggering it is so low they should be granted the exception. And I imagine if you train them on the procedure so they don't do it, the chance should be 0%.